Purificn. of aq. soln. of gas, e.g. hydrogen halide or ammonia - by desorbing excess gas, distilling azeotrope and absorbing gas in distillate

摘要

Purificn. of the aq. soln. of a gaseous material (I) from impurities involves desorption of the excess (I) present in the initial aq. soln., distn. of the remaining (azeotropic) liquid, which boils without change of compsn., and saturation of the distillate withthe desorbed (I). Desorption is carried out by heating the soln. to a temp. ensuring desorption of at least 95% of the excess (I) up to a temp. 1 deg. C below the b.pt. of the azeotropic liquid. The process is useful for purifying HF, HCl and NH3 solns. End prods. with a high degree of purity can be obtd. and the technology is simple.